Sewing machine needle bar and take-up operating means



Jan. 26, 1954 s. R. BELL SEWING MACHINE NEEDLE BAR AND TAKE-UP OPERATING MEANS Filed March 27, 1950 INVENTOR Sm/vnf fz ATToREY Patented Jan. 26, 1954 UNITED STATES PATENT OFFICE 'SEWING MACHINE NEEDLE BAR AND TAKE-UP OPERATING MEANS Sidney R. Bell, Stamford, Conn.

Application March 27, 1950, Serial No. 152,250

6 Claims. l

This invention relates to sewing machines and, particularly, to mechanism .for actuating the needle bar and thread take-up arm of a `sewing machine. More particularly, the invention deals with an operating mechanism of this type and kind which is `compact and arranged to operate Within a relatively small head, while at the same time, producing the desired stroke motions of the parts consistent with conventional practices.

The novel features of the invention 'will vbe best understood from the following description, when taken together with the accompanying drawing, in which certain embodiments of the invention are disclosed and, in which, `the separate parts are designated by suitable reference characters in each of the views and, in which:

Fig. l is a diagrammatic sectional view of the head en-d portion of an arm of a sewing machine, illustrating my improved drive mechanism.

Fig, 2 is a section on the .line 2-2 'of Fig. l, indicating part of the structure .in dot and dash lines.

Fig. 3 isa section substantially on the line 3 3 of Fig. l; and

Fig. 4 is a perspective ViewT of part of the drive mechanism detached.

In Fig. l of the drawing, I have shown at I the forward end portion of the arm of a sewing machine, having a head portion l! at its end, the arm and part of the head II being formed in a casting, around which may be arranged a casing or housing, diagrammatically outlined in dot and dash lines at i2. lMounted on the head II is a supplemental head lf3, in which a greater part of the drive mechanism is arranged which facilitates assemblage and disassemblage of the parts as will appear from the following description.

Extending through the arm lt is a rdrive shaft 'lll from any conventional drive, the shaft having a suitable bearing in the arm, as at I5. Fixed to the shaft is a main crank IS having a counterweight'portion Il in opposed arrangement with respect to a drive pin I8 of said crank.

The pin I8 extends into the supplemental head I 3 and rotatably mounted on the pin is a pinion I9 and needle bar operating crank 20, the crank and pinion being secured together.

The head ll has an internal gear '2l which is concentric to the axis of the shaft I4 and in connection with which the pinion I9 operates as the crank I6 is rotated.

Mounted in suitable bearings in the supplemental head It is a vertically reciprocating needle bar 22, in which is rotatably mounted acrank inl pin 23, having a large bushing portion 24 Voperating in .an enlarged cutout 25 in :the 'bar 22. The pin 23 extends into vand is xed to the crank 2.0, the pin having a head as at 26. The fixing ,of the pin 23 provides the definite rotary motion to a crank 2 which is keyed to the pin .2.3. It will also be noted from a Aconsideration lof Fig. 2 of the drawing that the pin 23 is alined denitely with the pitch diameter .of the Vpinion I9. The ratio of the pinion I9 to the :internal gear '2i .is tWo-to-one.

The crank 2l carries a drive-pin -28 on which is rotatably mounted the hub end 29 of atakeeup arm 36. Pivoted to the cover plate 'I3a of the supplemental head, as seen at 3|, is a fyokeshaped link 32. The link 32 is pivoted to the arm Sii, as seen at 33. The rfree end of the arm El! has an aperture or eye 34, through which a thread is free to pass.

Considering Fig. 2 of the drawing, it -Will be noted that, at 35, I have shown the upper portion of a presser foot `bar slidably mounted in the supplemental head I3, the Abar having an angularly extending pin 36 controlled by the usual cam lever 3'! for .raising a bar 35. The bar 35 is tensionally held in operative position by a spring 33, the tensionof which is controlled by an adjustable member .39. l

In the several views, the needle bar operating mechanism is shown at the bottom rof .its stroke. In other words, in this position, the crank 20, or the crank pin .23, is in its lowered position and the pinion I9 is at the lower portion ofthe internal gear 2 I.

Assuming that the shaft I4 is rotated inthe direction of the arrow 4.6, Fig. l, when this shaft has completed a one-quarter revolution, the pinion I9 would be at the left center Ahorizontal position in the internal gear 2l, as this gear is viewed in Fig. 2. In other words, kthe rpin ,I8 will have traversed one-.quarter of its orbitrepresented by the arrow 4I in Fig. .2. In the `same operation, the .pin 28 will have followed -the same identical path to the left, as .pin I8, substantially and the pin `23 has been Araised to a position in horizontal alinement with the Vpin I8, in other words, to have raised the needle bar a distance equivalent to the distance of vertical travel of the pin i8, plus the difference between the axis of the pin I8 and the axis of the pin 23.

Upon completing the rotation of the shaft I4 until the pin axis IB reaches the topdotted center position, here thepin axis 23 will assumefa positionabove the pin axis I3 equivalent to the spac- 3 ing between axes I8 and 23. In other words, considering Fig. 2 of the drawing, the pin axis 23 will have travelled from the point 42 to the point 43 of said gure along the straight line represented by the dot and dash arrow 44, this den-4 ing the full stroke motion of the needle bar 22 in one direction.

Completing rotation of the shaft I4 will result in returning the parts to the position shown in full lines in Figs. 1 and 2, the axis I8 moving in this last motion to the right of Fig. 2.

In other words, as the crank 20 and the pinion I 9 are driven by the crank pin I8, the pinion I9 traveling in the internal gear ZI is rotated, thus contributing the reciprocating drive to the needle bar 22. In this operation, the crank 21 is rotated to actuate the thread take-up arm 30 and, with the parts in the position shown in Figs. 1 and 2, the arm 30 is in a partially lowered position. Upon completing the one-quarter revolution of the shaft I4, as above described, the arm 30 will be moved to its lowest position, as indicated in Fig. 3 of the drawing. Then as the shaft completes the half turn, above mentioned, the link- 32 actuates to speed-up the upward travel of the arm and the arm will complete its upward stroke, as indicated in dot and dash lines in Fig. 3, after the axis I8 has started its downward travel or to a point completing substantially a three-quarter revolution of the drive shaft I4 and during the last quarter the arm 30 moves downwardly at a fast rate of speed and completes its downward movement in the earlier stages of upward movement of the needle bar 22.

From the foregoing, it will be apparent that, through a relatively simple crank and link motion housed within a relatively small head, full stroke can be contributed to a needle bar, as well as a thread pick-up arm in a free and easy motion. This construction eliminates the use of vertically elongated heads, as commonly experienced in sewing machines of the kind under consideration. Furthermore, this construction facilitates the production of relatively small machines and gives greater clearance, or work area, beneath the head, than is experienced with machines of general construction.

From the foregoing, it will be apparent that, through a relatively simple mechanism, the rotary drive motion of a crank is transmitted to a reciprocating motion in a needle bar and the crank stroke is amplified to the extent of the added drive of the pinion actuated needle bar operating crank.

For purposes of description, the pinion and crank assembly I9, 20 may be said to comprise a drive or actuating unit bodily driven by the main drive crank circumferentially with respect to the axis of the drive shaft. In this operation, the axis of this unit moves in a predetermined diameter distance defined by the greater upward and downward movement of the crank pin I8 and, in such movement and, by reason of the engagement of the pinion I9 with the internal gear 2l, the crank 23 is moved a materially greater distance, thus imparting a long reciprocating stroke motion to the needle bar within a relatively small head.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent is:

l. In sewing machines, an arm terminating at its end in a head, an actuating mechanism detachable with respect to said head, a drive shaft mounted in said arm and having, adjacent the 75 head, a main drive crank, said crank having a pin extending into said mechanism, a combined crank and pinion portion rotatably mounted on said pin, an internal gear in alinement with said pinion and in connection with which the pinion operates, the axis of said gear being common with the axis of said drive shaft, a needle bar, means for supporting the needle bar for vertical reciprocating movement in said mechanism, said last named crank having a crank pin rotatable in said needle bar and having an extension beyond said bar, a take-up actuating crank fixed to said crank pin, a take-up arm movably supported in said mechanism, and means for coupling said last named crank with said take-up arm for actuating the arm in the reciprocating drive of the needle bar by said mechanism.

2. In sewing machines employing a needle bar adapted for vertical reciprocating movement in the head of a machine and a thread take-up arm movably supported in said head, an actuating mechanism for imparting full stroke motion to the needle bar within boundaries of a relatively small head, said mechanism comprising a crank pinion unit bodily rotated through the medium of a drive crank through a predetermined circumferential path, an internal gear engaging the pinion in the drive motion thereof to rotate said unit, the crank of said unit including a crank pin rotatably coupled with the needle bar to reciprocate the needle bar a distance materially greater than the greatest diameter of travel of the axial portion of said pinion, said crank pin having another crank fixed thereto, and means coupling said last named crank With said arm.

3. In sewing machines employing a needle bar adapted for vertical reciprocating movement in the head of a machine and a thread take-up arm movably supported in said head, an actuating mechanism for imparting full stroke motion to the needle bar within boundaries of a relatively small head, said mechanism comprising a crank pinion unit bodily rotated through the medium of a drive crank through a predetermined circum ferential path, an internal gear engaging the pinion in the drive motion thereof to rotate said unit, the crank of said unit including a crank pin rotatably coupled with the needle bar to reciprocate the needle bar a distance materially greater than the greatest diameter of travel of the axial portion of said pinion, said crank pin having another crank fixed thereto, means coupling said last named crank with said arm, and means for guiding said arm in the actuation thereof by said last named crank.

4. In sewing machines employing a needle bar adapted for vertical reciprocating movement in the head of a machine and a thread take-up arm movably supported in said head, an actuating mechanism for imparting full stroke motion to the needle bar within boundaries of a relatively small head, said mechanism comprising a crank pinion unit bodily rotated through the medium of a drive crank through a predetermined circumfcrential path, an internal gear engaging the pinion in the drive motion thereof to rotate said unit, the crank of said unit including a crank pin rotatably coupled with the needle bar to reciprocate the needle bar a distance materially greater than the greatest diameter of travel of the axial portion of said pinion, said crank pin having another crank xed thereto, means coupling said last named crank with said arm, means for guiding said arm in the actuation thereof by said last named crank, and said last named means comprising a pivotally supported link.

5. In a sewing machine employing a drive shaft, a drive crank at one end of the shaft and a pin extending from said crank, an internal gear en circling said pin, a drive unit for actuating a needle bar and thread take-up arm, said unit comprising a pair of driven cranks including a crank pin joining said cranks and rotatable in the needle bar with the cranks disposed at opposed sides of the bar, the other end of one of said driven cranks having an aperture receiving the pin of said drive crank for actuating said pair of driven cranks, a pinion mounted on said last named pin between the drive crank and first named driven crank and operatively engaging said internal gear to control the drive of said driven cranks, the other end of the other of said driven cranks having an outwardly extending pin, one end portion of the thread take-up arm of 2O the machine being mounted on said last named pin, and a link forming a pivotal support of the arm adjacent said last named pin.

6. In a sewing machine employing a needle bar and a thread take-up arm, an actuating mechanism comprising a crank unit rotatably coupled With said needle bar and bodily rotatable through the medium of a drive crank of the machine through a predetermined circumferential path in imparting reciprocating movement to said needle bar, means pivotally coupling one end of said take-up arm with said crank unit, a link pivotally supported in the machine, and means pivotally coupling the free end of the link with the arm adjacent the pivotal coupling of the arm with the crank unit to control actuation of said arm.

SIDNEY R. BELL.

References Cited in the file of this patent UNITED STATES PATENTS Number 

